The famously minuscule memory span of fish is in doubt after scientists discovered that at least one species is able to remember where it was given food for at least 12 days.

The research on African cichlids was inspired by anecdotal reports of their intelligence from aquarium owners.

"Some people even believe that their cichlids watch television with them," said study leader Dr Trevor Hamilton, from MacEwan University in Canada .

For the research, cichlids were trained to enter a particular zone of an aquarium to receive a food reward.

After a 12 day rest period, they were re-introduced to the aquarium and their movements were tracked.

The fish showed a distinct preference for the area previously associated with the food reward, suggesting they remembered being fed there.

They were also able to stop making the association after further training when the food was linked to a different stimulus.

"Fish that remember where food is located have an evolutionary advantage over those that do not," said Dr Hamilton, who presented the findings at the Society for Experimental Biology's annual meeting in Manchester.

"If they are able to remember that a certain area contains food without the threat of a predator, they will be able to go back to that area. Decreases in the availability of food would promote the survival of species that can remember the location of food sources."

Wild cichlids have a varied diet that includes snails, small fish, insects and plants and are thought to associate locations with preferred sources of food.

The scientists are now investigating whether the strength of fish memories are affected by environmental conditions or drugs.